N2 -Substituted-L-arginine derivatives and the pharmaceutically acceptable acid addition salts thereof

ABSTRACT

N 2  -substituted-L-arginine esters and amides, and the pharmaceutically acceptable acid addition salts thereof have been found to be effective as pharmaceutical agents for the inhibition and suppression of thrombosis.

This application is a divisional of application Ser. No. 703,704, filedJuly 8, 1976 which now issued to U.S. Pat. No. 4,069,325 of Jan. 17,1978 which is a CIP of Ser. No. 671,436, filed Mar. 29, 1976, now U.S.Pat. No. 4,066,758, which is a divisional application of Ser. No.622,390, filed Oct. 14, 1975, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to the discovery of certain new and useful N²-substituted-L-arginine derivatives and the pharmaceutically acceptableacid addition salts thereof, which are of especial value in view oftheir outstanding antithrombotic properties.

2. Description of the Prior Art

In the past, there have been many attempts to obtain new and improvedagents for the treatment of thrombosis. Of these, N²-(p-tolylsulfonyl)-L-arginine esters are known to be effective indissolving blood clots. (U.S. Pat. No. 3,622,615, issued Nov. 23, 1971)

However, there is a continuing need for a highly specific inhibitor onthrombin for the control of thrombosis. Accordingly, we have discoverednovel N² -substituted-L-arginine derivatives which exhibitantithrombotic activity.

SUMMARY OF THE INVENTION

In summary, the compounds of this invention can be represented by theformula (I): ##STR1## wherein R is selected from the group consisting of(1)--OR₁, wherein R₁ is selected from the group consisting of C₁ -C₁₀alkyl, C₃ -C₁₀ cycloalkyl, C₁ -C₁₀ haloalkyl, C₂ -C₁₀ alkoxyalkyl, C₂-C₁₀ alkenyl, C₂ -C₁₀ alkynyl and C₇ -C₁₅ aralkyl; ##STR2## wherein R₂and R₃ are selected from the group consisting of hydrogen, C₁ -C₁₀alkyl, C₇ -C₁₅ aralkyl, and C₁ -C₁₀ alkyl substituted with a groupselected from C₁ -C₁₀ alkoxy, C₂ -C₁₀ alkoxycarbonyl and carboxy; and##STR3## wherein Z is a divalent group which consists of two or moregroups selected from methylene -CH₂ - and monosubstituted methylene##STR4## (wherein R₄ is selected from the group consisting of C₁ -C₁₀alkyl and C₁ -C₁₀ alkoxy); and zero or one or more than one groupselected from oxy -O-, thio -S-, alkyl substituted imino ##STR5##(wherein R₅ is C₁ -C₁₀ alkyl) and acyl substituted imino ##STR6##(wherein R₆ is C₁ -C₁₀ alkyl), which are combined in an arbitrary order,the number of the combined groups being up to 20; and R' is selectedfrom the group consisting of ##STR7## wherein R" and R'" when consideredseparately are C₁ -C₁₀ alkyl, or R" and R'" when taken together are C₁-C₁₀ alkylene; ##STR8## Also encompassed within this invention arepharmaceutically acceptable acid addition salts thereof.

This invention also relates to a method for inhibiting activity andsuppressing activation of thrombin in vivo, which comprises introducinginto a living body a pharmaceutically effective amount of an N²-substituted-L-arginine ester or amide or the pharmaceuticallyacceptable acid addition salt thereof.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

As summarized above, this invention relates to a group of N²-substituted-L-arginine esters and amides of the formula (I): ##STR9##wherein R is represented by the formula (1)-OR₁, ##STR10## each of whichwill be described below in detail.

(1) In case where R is --OR₁

R₁ is selected from the group consisting of C₁ -C₁₀ alkyl such asmethyl, ethyl, propyl, isopropyl, butyl, tert-butyl, pentyl, hexyl orthe like; C₃ -C₁₀ cycloalkyl such as cyclopropyl, cyclohexyl or thelike; C₁ -C₁₀ haloalkyl such as 2-chloroethyl, 3-chloropropyl,4-chlorobutyl or the like; C₂ -C₁₀ alkoxyalkyl such as 2-methoxyethyl,2-ethoxyethyl or the like; C₂ -C₁₀ alkenyl such as allyl, 2-butenyl orthe like; C₂ -C₁₀ alkynyl such as 3-butynyl or the like; and C₇ -C₁₅aralkyl such as benzyl, phenethyl or the like.

(2) In case where R is ##STR11## R₂ and R₃ are selected from the groupconsisting of hydrogen; C₁ -C₁₀ alkyl such as methyl, ethyl, propyl,isopropyl, butyl, isobutyl, pentyl, hexyl, heptyl or the like; C₇ -C₁₅aralkyl such as benzyl, phenethyl, 3-phenylpropyl or the like; and C₁-C₁₀ alkyl substituted with a group selected from C₁ -C₁₀ alkoxy, C₂-C₁₀ alkoxycarbonyl and carboxy such as 2-methoxyethyl, 3-methoxypropyl,2-ethoxyethyl, ethoxycarbonylmethyl, 2-methoxycarbonylethyl,2-ethoxycarbonylethyl, 3-ethoxycarbonylpropyl, carboxymethyl,2-carboxyethyl or the like.

(3) In case where ##STR12## Z is a divalent group which consists of twoor more groups selected from methylene -CH₂ - and monosubstitutedmethylene ##STR13## (wherein R₄ is selected from the group consisting ofC₁ -C₁₀ alkyl and C₁ -C₁₀ alkoxy), and zero or one or more than onegroup selected from oxy -O-, thio -S-, alkyl substituted imino ##STR14##(wherein R₅ is C₁ -C₁₀ alkyl) and acyl substituted imino ##STR15##(wherein R₆ is C₁ -C₁₀ alkyl), which are combined in an arbitrary order,the number of the combined groups being normally up to 20.

More particularly, R includes 1-polymethyleneiminyl groups or thederivatives thereof, such as 1-aziridinyl, 1-azetidinyl,3-methoxy-1-azetidinyl, 3-ethoxy-1-azetidinyl, 1-pyrrolidinyl,piperidino, 4-methylpiperidino, 4-ethylpiperidino, 4-propylpiperidino,4-isopropylpiperidino, 2-methylpiperidino, 3-methylpiperidino,4-methoxypiperidino, 1-hexamethyleneiminyl, 1-octamethyleneiminyl, andthe like; an oxazole or thiazole series such as 3-oxazolidinyl,3-thiazolidinyl, and the like; an isoxazole or isothiazole series suchas 2-isoxazolidinyl, 2-isothiazolidinyl, and the like; an oxazine seriessuch as morpholino, 2,6-dimethylmorpholino, tetrahydro-1,3-oxazin-3-yl,and the like; a thiazine series such as tetrahydro-1,4-thiazin-4yl, andthe like; 4-methyl-1-piperazinyl, 4-acetyl-1-piperazinyl, and the like.The preferred R groups are the following:

(1) In case where R is --OR₁ C₁ -C₈ alkoxy, cyclohexyloxy, C₂ -C₆omega-chloroalkoxy, C₂ -C₆ omega-alkoxyalkoxy, C₃ -C₆ alkenyloxy, C₂ -C₆alkynyloxy, C₇ -C₉ aralkyloxy

(2) In case where R is ##STR16## C₁ -C₉ alkylamino, C₂ -C₆omega-alkoxyalkylamino, C₃ -C₈ omega-alkoxycarbonylalkylamino, C₇ -C₁₀aralkylamino, C₂ -C₁₀ dialkylamino

(3) In case where R is ##STR17## C₃ -C₁₀ N,N-polymethyleneiminyl; C₃-C₁₀ N,N-polymethyleneiminyl substituted with a group selected from C₁-C₅ alkyl and C₁ -C₅ alkoxy; tetrahydro-1, n-oxazin-n-yl (n=2, 3 or 4);tetrahydro-1, n-thiazin-n-yl (n=2,3 or 4); 1-piperazinyl substitutedwith a group selected from C₁ -C₅ alkyl and C₁ -C₅ acyl The mostpreferred R groups are the following:

(1) In case where R is --OR₁ propoxy, butoxy, hexyloxy, cyclohexyloxy,3-chloropropoxy, 2-methoxyethoxy, 2-butenyloxy, 3-butynyloxy, benzyloxy

(2) In case where R is ##STR18## butylamino, 2-methoxyethylamino,2-methoxycarbonylethylamino, 2-ethoxycarbonylethylamino, benzylamino,N-methyl-N-butylamino

(3) In case where R is ##STR19## piperidino, hexamethyleneiminyl,4-methylpiperidino, 4-ethylpiperidino, 4-methoxypiperidino, morpholino,tetrahydro-1,4-thiazin-4-yl, 4-methyl-1-piperazinyl,4-acetyl-1-piperazinyl

In the above formula (I), R' is a member selected from the groupconsisting of (a) substituted naphthyl ##STR20## wherein R" and R'" whenconsidered separately are respectively C₁ -C₁₀ (preferably C₁ -C₅) alkylsuch as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, tert-butyl orthe like; or R" and R'" when taken together are C₁ -C₁₀ (preferably C₁-C₅) alkylene such as methylene, ethylene, trimethylene or the like; thealkoxy (--OR", --OR'") or the alkylenedioxy (--OR"--R'"O--) group andthe sulfonyl group may be located at any of the 1- to 8-position of thenaphthalene nucleus; normally, the sulfonyl group is located at 1- or2-position, and the alkylenedioxy group is a 6,7-alkylenedioxy group;##STR21## Illustrative of the typical N² -substituted-L-arginine estersand amides of this invention are the following:

(1) In the case of the ester derivatives

N² -(6,7-dimethoxy-2-naphthalenesulfonyl)-L-arginine propyl ester

N² -(6,7-dimethoxy-2-naphthalenesulfonyl)-L-arginine butyl ester

N² -(6,7-dimethoxy-2-naphthalenesulfonyl)-L-arginine benzyl ester

N² -(6,7-dimethoxy-2-naphthalenesulfonyl)-L-arginine 3-chloropropylester

N² -(6,7-dimethoxy-2-naphthalenesulfonyl)-L-arginine 2-methoxyethylester

N² -(6,7-dimethoxy-2-naphthalenesulfonyl)-L-arginine 3-butynyl ester

N² -(6,7-dimethoxy-2-naphthalenesulfonyl)-L-arginine 2-butenyl ester

(2) In the case of the amide derivatives wherein R is ##STR22## N²-(6,7-dimethoxy-2-naphthalenesulfonyl)-N-(2-methoxyethyl)-L-argininamide

N² -(6,7-dimethoxy-2-naphthalenesulfonyl)-N-benzyl-L-argininamide

N² -(2-xanthenesulfonyl)-N-methyl-N-butyl-L-argininamide

(3) In the case of the amide derivatives wherein R is ##STR23##4-methyl-1-[N²-(6,7-dimethoxy-2-naphthalenesulfonyl)-L-arginyl]piperidine

4-ethyl-1-[N²-(6,7-dimethoxy-2-naphthalenesulfonyl)-L-arginyl]piperidine

1-[N²-(6,7-dimethoxy-2-naphthalenesulfonyl)-L-arginyl]hexamethyleneimine

4-[N² -(6,7-dimethoxy-2-naphthalenesulfonyl)-L-arginyl]morpholine

4-methoxy-1-[N²-(6,7-dimethoxy-2-naphthalenesulfonyl)-L-arginyl]piperidine

4-methyl-1-[N²-(4,6-dimethoxy-2-naphthalenesulfonyl)-L-arginyl]piperidine

4-ethyl-1-[N²-(4,6-dimethoxy-2-naphthalenesulfonyl)-L-arginyl]piperidine

4-ethyl-1-[N²-(2H-3,4-dihydro-1,5-benzodioxepin-7-sulfonyl)-L-arginyl]piperidine

4-methyl-1-[N²-(2H-3,4-dihydro-1,5-benzodioxepin-7-sulfonyl)-L-arginyl]piperidine

4-ethyl-1-[N²-(3-methoxy-(2H-3,4-dihydro-1,5-benzodioxepin)-7-sulfonyl)-L-arginyl]piperidine

4ethyl-1-[N² -(2-xanthenesulfonyl)-L-arginyl]piperidine

4-ethyl-1-[N² -(2-dibenzofuransulfonyl)-L-arginyl]piperidine

4-ethyl-1-[N² -(4-dibenzofuransulfonyl)-L-arginyl]piperidine

4-ethyl-1-[N² -(dibenzo-p-dioxin-2-sulfonyl)-L-arginyl]piperidine

1-[N² -(4-dibenzofuransulfonyl)-L-arginyl]hexamethyleneimine

The following compounds are most preferred due to their high level ofantithrombotic activity.

N² -(6,7-dimethoxy-2-naphthalenesulfonyl)-L-arginine butyl ester

N²-(6,7-dimethoxy-2-naphthalenesulfonyl)-N-(2-methoxyethyl)-L-argininamide

4-methyl-1-[N²-(6,7-dimethoxy-2-naphthalenesulfonyl)-L-arginyl]piperidine

4-ethyl-1-[N²-(6,7-dimethoxy-2-naphthalenesulfonyl)-L-arginyl]piperidine

4-methoxy-1-[N²-(6,7-dimethoxy-2-naphthalenesulfonyl)-L-arginyl]piperidine

4-methyl-1-[N²-(4,6-dimethoxy-2-naphthalenesulfonyl)-L-arginyl]piperidine

4-ethyl-1-[N²-(4,6-dimethoxy-2-naphthalenesulfonyl)-L-arginyl]piperidine

4-ethyl-1-[N² -(2-xanthenesulfonyl)-L-arginyl]piperidine

4-ethyl-1-[N² -(4-dibenzofuransulfonyl)-L-arginyl]piperidine

4-ethyl-1-[N² -(dibenzo-p-dioxin-2-sulfonyl)-L-arginyl]piperidine

The pharmaceutically acceptable acid addition salts of the abovecompounds are of course also included within the scope of thisinvention.

The above compounds are intended only to illustrate the variety ofstructures which can be used in the process of this invention, and theabove listing is not to be construed as limiting the scope of theinvention.

These typical compounds are highly potent in their antithromboticactivity.

For the preparation of the compounds of this invention, various methodscan be employed depending upon the particular starting materials and/orintermediates involved. Successful preparation of these compounds ispossible by way of several synthetic routes which are outlined below.

(1) Preparation of N² -substituted-L-arginine esters

(a) Esterification of an N² -substituted-L-arginine

(i) Reaction of an N² -substituted-L-arginine and an alcohol

This process may be illustrated as follows: ##STR24## In the aboveformulas, R is --OR₁, in which R₁ is as defined herein above, and R' isas defined herein above.

The N² -substituted-L-arginine ester (I) is prepared by esterifying anN² -substituted-L-arginine (II) with an alcohol (III).

The esterification can be effected by reacting the N²-substituted-L-arginine with at least 5 equivalents of the alcohol inthe presence of at least an equimolar amount of an acid catalyst such ashydrogen chloride, sulfuric acid, toluenesulfonic acid or the like.

The reaction is generally carried out without an added solvent or in asuitable reaction-inert solvent at a temperature of 0° C. to the boilingtemperature of the alcohol or the solvent for a period of 10 minutes to15 hours. The preferred solvents are those which form an azeotropicmixture with water and facilitates the removal of water formed duringthe reaction.

Examples of such solvents are benzene, toluene, xylene, cyclohexane,carbon tetrachloride and dichloromethane.

After the reaction is complete, the alcohol and/or the solvent isdistilled off to give the N² -substituted-L-arginine ester (I) or anacid addition salt thereof, which can be purified by recrystallizationfrom a combination of solvents such as ethyl ether, alcohols andacetone, or by reprecipitation by adding ether to the alcohol solutionthereof.

The acid addition salt of the N² -substituted-L-arginine ester can beeasily converted to the corresponding ester by adjusting the pH of thesolution.

(ii) Reaction of an N² -substituted-L-arginine, an alcohol and a thionylhalide.

The N² -substituted-L-arginine ester (I) can be prepared by reacting anN² -substituted-L-arginine (II), an alcohol (III) and a thionyl halidesuch as thionyl chloride or thionyl bromide.

The thionyl halide is preferably used in an amount not less than 2 molesper mole of the N² -substituted-L-arginine.

The other reaction conditions such as reaction temperature, reactiontime, amount of the alcohol to be used; and the procedures of separationand purification of the product are as described above in theesterification with an acid catalyst.

According to this method, the product is usually a halogeno acid salt ofthe N² -substituted-L-arginine ester.

The N² -substituted-L-arginine (II) can be esterified by many otherprocedures.

The N² -substituted-L-arginines (II) starting materials are readilyobtained by reacting arginine and a sulfonyl halide (preferably achloride) of the formula (IV):

    r'so.sub.2 x                                               (iv)

wherein R' is as defined herein above and X is halogen, in the presenceof a base such as K₂ CO₃, KOH, NaOH, triethylamine or pyridine.

(b) Condensation of an L-arginine ester with a sulfonyl halide

This process may be illustrated as follows: ##STR25## In the aboveformulas, R is --OR₁ wherein R₁ is as defined herein above; R' is asdefined herein above; and X is halogen.

The N² -substituted-L-arginine ester (I) is prepared by the condensationof an L-arginine ester (V) with a substantially equimolar amount of asulfonyl halide (IV), preferably a chloride.

The condensation reaction is generally effected in a suitablereaction-inert solvent in the presence of an excess of a base, such asan organic base (triethylamine, pyridine) or a solution of an inorganicbase (sodium hydroxide, potassium carbonate), at a temperature of 0° C.to the boiling temperature of the solvent for a period of 10 minutes to15 hours.

The preferred solvents for the condensation include dichloromethane,diethyl ether-water and dioxane-water.

After the reaction is complete, the formed salt is extracted with water,and the solvent is removed by such standard means as evaporation underreduced pressure to give the N² -substituted-L-arginine ester (I), whichcan be purified by trituration or recrystallization from a suitablesolvent, such as diethyl ether-tetrahydrofuran, diethyl ether-methanoland water-methanol, or may be chromatographed on silica gel.

The L-arginine ester (V) starting materials are most generally preparedby reacting L-arginine with an alcohol in the presence of an acidcatalyst.

(2) Preparation of N² -substituted-L-argininamides

(a) Condensation of an L-argininamide with a sulfonyl halide

This process may be illustrated as follows: ##STR26## In the aboveformulas, R is ##STR27## wherein R₂, R₃ and Z are as defined hereinabove; R' is as defined herein above; and X is halogen. The N²-substituted-L-argininamide (I) is prepared by condensing anL-argininamide (V) with a substantially equimolar amount of a sulfonylhalide (IV), preferably a chloride, in the presence of a base.

The reaction conditions are the same as those described in the Process(1)(b) (condensation of an L-arginine ester with a sulfonyl halide).

The L-argininamides (V) starting materials required for the condensationreaction can be prepared by protecting the guanidino and α-amino groupof the arginine via nitration, acetylation, formylation, phthaloylation,trifluoroacetylation, p-methoxybenzyloxycarbonylation, benzoylation,benzyloxycarbonylation, tert-butoxycarbonylation or tritylation and thencondensing the formed N^(G) -substituted-N² -substituted-L-arginine witha corresponding amine by such a conventional process as the acidchloride method, azide method, mixed anhydride method, activated estermethod or carbodiimide method, and thereafter selectively removing theprotective group.

(b) Removal of the N^(G) -substituent from an N^(G) -substituted-N²-substituted-L-argininamide

This process may be illustrated as follows: ##STR28##

In the above formulas, R is ##STR29## wherein R₂, R₃ and Z are asdefined herein above; R' is as defined herein above; X is halogen; Y" isa protective group for the amino group, such as benzyloxycarbonyl ortert-butoxycarbonyl; and Y and Y' are hydrogen and protective groups forthe guanidino group, such as nitro, tosyl, trityl, oxycarbonyl or thelike.

At least one of Y and Y' is a protective group for the guanidino group.

The N² -substituted-L-argininamide (I) is prepared by removing the N^(G)-substituent from an N^(G) -substituted-N² -substituted-L-argininamide(IX) by means of acidolysis or hydrogenolysis.

The acidolysis is generally effected by contacting the N^(G)-substituted-N² -substituted-L-argininamide (IX) and an excess of anacid such as hydrogen fluoride, hydrogen chloride, hydrogen bromide ortrifluoroacetic acid, without a solvent or in a solvent, such as anether (tetrahydrofuran, dioxane), an alcohol (methanol, ethanol) oracetic acid at a temperature of -10° C. to 100° C., and preferably atroom temperature for a period of 10 minutes to 24 hours.

The products are isolated by evaporation of the solvent and the excessacid, or by trituration with a suitable solvent followed by filtrationand drying.

Because of the use of the excess acid, the products are generally theacid addition salts of the N² -substituted-L-argininamides (I), whichcan be easily converted to a free amide by neutralization.

The removal of the nitro group and the oxycarbonyl group, e.g.,benzyloxycarbonyl, p-nitrobenzyloxycarbonyl, is readily accomplished bythe hydrogenolysis.

The hydrogenolysis is effected in a reaction-inert solvent, e.g.,methanol, ethanol, tetrahydrofuran or dioxane, in the presence of ahydrogen-activating catalyst, e.g., Raney nickel, palladium, orplatinum, in a hydrogen atmosphere at a temperature of 0° C. to theboiling temperature of the solvent for a period of 2 hours to 120 hours.

The hydrogen pressure is not critical, and atmospheric pressure issufficient.

The N² -substituted-L-argininamides (I) are isolated by filtration ofthe catalyst followed by evaporation of the solvent.

The N² -substituted-L-argininamides can be purified in the same manneras described above.

The N^(G) -substituted-N² -substituted-L-argininamides (IX) startingmaterials can be prepared by condensing an N^(G) -substituted-N²-substituted-L-arginine (VI) (generally the N² -substituent is aprotective group for the amino group, such as benzyloxycarbonyl,tert-butoxycarbonyl, or the like) and a corresponding amine (III) viathe azide method, mixed anhydride method, activated ester method,carbodiimide method or the like, selectively removing only the N²-substituent of an N^(G) -substituted-N² -substituted-L-argininamide(VII) by means of catalytic hydrogenolysis or acidolysis, and thencondensing the thus obtained N^(G) -substituted-L-argininamide (VIII)with a sulfonyl halide (IV), preferably a chloride in the presence of abase in a solvent. These reaction conditions are as described above inthe condensation of an L-argininamide with a sulfonyl halide, and theremoval of the N^(G) -substituent from an N^(G) -substituted-N²-substituted-L-argininamide.

(c) Condensation of an N² -substituted-L-arginyl halide with an amine

This process may be illustrated as follows: ##STR30## In the aboveformulas, R is ##STR31## wherein R₂, R₃ and Z are as defined hereinabove; R' is as defined herein above; and X is halogen. The N²-substituted-L-argininamide (I) is prepared by the condensation of an N²-substituted-L-arginyl halide (X), preferably a chloride with at leastan equimolar amount of an amine (III).

The condensation reaction can be carried out without an added solvent.However, satisfactory results will be obtained with the use of a solventsuch as basic solvents (dimethylformamide, dimethylacetamide, etc.) orhalogenated solvents (chloroform, dichloromethane, etc.)

The amount of the solvent to be used is not critical and may vary fromabout 5 to 100 times the weight of the N² -substituted-L-arginyl halide(X).

Preferred condensation reaction temperatures are in the range of from-10° C. to room temperature. The reaction time is not critical, butvaries with the amine (III) employed. In general, a period of from 5minutes to 10 hours is operable.

The obtained N² -substituted-L-argininamide can be isolated and purifiedin the same manner as described above.

The N² -substituted-L-arginyl halide (X) starting materials required forthe condensation reaction can be prepared by reacting an N²-substituted-L-arginine (II) with at least an equimolar amount of ahalogenating agent such as thionyl chloride, phosphorous oxychloride,phosphorus trichloride, phosphorous pentachloride or phosphorustribromide. The halogenation can be carried out with or without an addedsolvent.

The preferred solvents are chlorinated hydrocarbons such as chloroformand dichloromethane, and ethers such as tetrahydrofuran and dioxane.

The amount of the solvent to be used is not critical and may vary fromabout 5 to 100 times the weight of the N² -substituted-L-arginine.Preferred reaction temperatures are in the range of -10° C. to roomtemperature. The reaction time is not critical, but varies with thehalogenating agent and reaction temperature. In general, a period of 15minutes to 5 hours is operable.

(d) Guanidylation of an N² -substituted-L-ornithinamide or an acidaddition salt thereof

This process may be illustrated as follows: ##STR32## In the aboveformulas, R is ##STR33## wherein R₂, R₃ and Z are as defined hereinabove; and R' is as defined herein above.

The N² -substituted-L-argininamide (I) is prepared by guanidylating anN² -substituted-L-ornithinamide (XI) with an ordinary guanidylatingagents such as an O-alkylisourea, S-alkylisothiourea,1-guanyl-3,5-dimethylpyrazole or carbodiimide. The preferredguanidylating agents are the O-alkylisourea and the S-alkylisothiourea.

The guanidylation of the N² -substituted-L-ornithinamide (XI) with theO-alkylisourea or S-alkylisothiourea is generally effected in a solventin the presence of a base at a temperature of from 0° C. to the boilingtemperature of the solvents for a period of from 30 minutes to 50 hours.

Examples of the preferred base are triethylamine, pyridine, sodiumhydroxide and sodium methoxide. The base is used in an amount of 0.01 to0.1 equivalent to the N² -substituted-L-ornithinamide. Examples of thepreferred solvent are water, water-ethanol and water-dioxane.

After the reaction is complete, the N² -substituted-L-argininamide (I)is isolated by evaporation of the solvent followed by removal of theexcess base and the formed salt by a water wash.

(e) Reaction of an N² -substituted-L-arginine ester and a primary aminep This process may be illustrated as follows: ##STR34## In the aboveformulas, R₂ and R' are as defined herein above; and R₇ is C₁ -C₁₀alkyl.

The N² -substituted-L-argininamide represented by the formula (XIV) canbe prepared by the reaction of an N² -substituted-L-arginine ester (XII)and about 2 to 10 equivalents of a primary amine (XIII).

The reaction is generally carried out without an added solvent or in asolvent such as an alcohol (methanol, ethanol), an ether (ethyl ether,tetrahydrofuran), a hydrocarbon (benzene, toluene), a halogenatedhydrocarbon (chloroform, dichloromethane) or water at room temperaturefor a period of several hours to several days. In order to acceleratethe reaction, the reaction mixture may be heated to a temperature of upto the boiling point of the amine or the solvent. Alternatively, a basiccatalyst such as sodium methoxide or pyridine may be added to thereaction mixture.

After the reaction is complete, the formed N²-substituted-L-argininamide (XIV) is isolated by filtration or byevaporation of the excess amine and/or the solvent, washed with water,and then purified by recrystallization from a suitable solvent such aswater-methanol.

The N² -substituted-L-arginine esters or amides (I) of this inventionform acid addition salts with any of a variety of inorganic and organicacids. The product of the reactions described above can be isolated inthe free form or in the form of acid addition salts. In addition, theproduct can be obtained as pharmaceutically acceptable acid additionsalts by reacting one of the free bases with an acid, such ashydrochloric, hydrobromic, hydroiodic, nitric, sulfuric, phosphoric,acetic, citric, maleic, succinic, lactic, tartaric, gluconic, benzoic,methanesulfonic, ethanesulfonic, benzenesulfonic, p-toluenesulfonic acidor the like. Likewise, treatment of the acid addition salts with a baseresults in a regeneration of the free amide or ester.

As stated above, the N² -substituted-L-arginine esters and amides, andthe salts thereof of this invention are characterized by highly specificinhibitory activity against thrombin, and therefore, these compounds areuseful in the determination of thrombin in blood as diagnostic reagents,and/or for the medical control or prevention of thrombosis. Theantithrombotic activities of the N² -substituted-L-arginine esters andamides of this invention were compared with that of a knownantithrombotic agent, N² -(p-tolylsulfonyl)-L-arginine methyl ester, bydetermining the fibrinogen congulation time. The measurement of thefibrinogen coagulation time was conducted as follows: An 0.8 ml aliquotof a fibrinogen solution, which has been prepared by dissolving 150 mgof bovine fibrinogen (Cohn fraction 1) supplied by Armour Inc. in 40 mlof a borate saline buffer (pH 7.4), was mixed with 0.1 ml of a boratesaline buffer, pH 7.4, (control) or a sample solution in the samebuffer, and 0.1 ml of a thrombin solution (5 units/ml) supplied byMochida Pharmaceutical Co., Ltd. was added to the solutions in an icebath. Immediately after mixing, the reaction mixture was transferredfrom the ice bath to a bath maintained at 25° C. Coagulation times weretaken as the period between the time of transference to the 25° C. bathand the time of the first appearance of fibrin threads. In the caseswhere no drug samples were added, the coagulation time was 50-55seconds.

The experimental results are summarized in TABLE 1. The term"concentration required to prolong the coagulation time by a factor oftwo" is the concentration of an active ingredient required to prolongthe normal coagulation time of 50-55 seconds to 100-110 seconds.

The concentration required to prolong the coagulation time by a factorof two for the known antithrombotic agent, N²-(p-tolysulfonyl)-L-arginine methyl ester, was 1,100 μM.

The inhibitors are shown in TABLE 1 by indicating R and R' in theformula (1) and the addition moiety.

When a solution containing an N² -substituted-L-arginine ester or amideof this invention was administered intravenously into animal bodies, thehigh antithrombotic activity in the circulating blood was maintained forfrom one to three hours. The half-life for decay of the antithromboticcompounds of this invention in circulating blood was shown to beapproximately 30 minutes; the physiological conditions of the hostanimals (rat, rabbit, dog and chimpanzee) were well maintained. Theexperimental decrease of fibrinogen in animals caused by infusion ofthrombin was satisfactorily controlled by simultaneous infusion of thecompounds of this invention.

The acute toxicity values (LD₅₀) determined by oral administration ofsubstances of formula (I) in mice (male, 20 g) range from about 1,000 to10,000 milligrams per kilogram of body weight. The therapeutic agents ofthis invention may be administered alone or in combination withpharmaceutically acceptable carriers, the proportion of which isdetermined by the solubility and chemical nature of the compound, chosenroute of administration and standard pharmaceutical practice. Forexample, the compounds may be injected parenterally, that is,intramuscularly, intravenously or subcutaneously. For parenteraladministration, the compounds may be used in the form of sterilesolutions containing other solutes, for example, sufficient saline orglucose to make the solution isotonic. The compounds may be administeredorally in the form of tablets, capsules, or granules containing suitableexcipients such as starch, lactose, white sugar and the like. Thecompounds may be administered sublingually in the form of troches orlozenges in which each active ingredient is mixed with sugar or cornsyrups, flavoring agents and dyes, and then dehydrated sufficiently tomake the mixture suitable for pressing into solid form. The compoundsmay be administered orally in the form of solutions which may containcoloring and flavoring agents. Physicians will determine the dosage ofthe present therapeutic agents which will be most suitable, and dosagesvary with the mode of administration and the particular compound chosen.In addition, the dosage will vary with the particular patient undertreatment.

When the composition is administered orally, a larger quantity of theactive agent will be required to produce the same effect as caused witha smaller quantity given parenterally. The therapeutic dosage isgenerally 10-50 mg/kg of active ingredient parenterally, 10-500 mg/kgorally per day.

Having generally described the invention, a more complete understandingcan be obtained by reference to certain specific examples, which areincluded for purposes of illustration only and are not intended to belimiting unless otherwise specified.

EXAMPLE 1

To 1.0 g (0.0018 mole ) of 4-ethyl-1-[N^(G) -nitro-N²-(6,7-dimethoxy-2-naphthalenesulfonyl)-L-arginyl]piperidine were added5.7 g (0.0053 mole) of anisole and 3 ml of hydrogen fluoride whilecooling with Dry-ice/acetone, and the mixture was stirred for 30 minutesin an ice bath. The anisole and the excess hydrogen fluoride wereevaporated at reduced pressure with cooling to afford an oily product,which was slurried with 100 ml of dry ethyl ether. The ether layer wasseparated by decantation, and the obtained powder was dissolved inmethanol, reprecipitated with ethyl ether, and then filtered to give4-ethyl-1-[N²-(6,7-dimethoxy-2-naphthalenesulfonyl)-L-arginyl]piperidinehydrofluoride in the powder form in a yield of 75%.

    ______________________________________                                        Elemental analysis: as C.sub.25 H.sub.37 O.sub.5 N.sub.5 S . HF                           C       H         N                                               ______________________________________                                        Calculated (%)                                                                              55.64     7.10      12.98                                       Found (%)     55.50     7.12      12.87                                       ______________________________________                                    

EXAMPLE 2

Into a suspension of 1.0 g (0.00186 mole) of 4-[N^(G) -nitro-N²-(6,7-dimethoxy-2-naphthalenesulfonyl)-L-arginyl] morpholine and 0.1 gof palladium black in 30 ml of ethanol and 10 ml of acetic acid waspassed hydrogen gas for 60 hours at room temperature. Upon completion ofthe reaction, the catalyst was filtered off, and the solvent wasevaporated under reduced pressure to give a viscous oily residue, whichwas taken up in methanol and reprecipitated with ether to afford 4-[N²-(6,7-dimethoxy-2-naphthalenesulfonyl)-L-arginyl] morpholine acetate inthe powder form in a yield of 82%.

    ______________________________________                                        Elemental analysis: as C.sub.22 H.sub.31 O.sub.6 N.sub.5 S . CH.sub.3         COOH                                                                                      C       H         N                                               ______________________________________                                        Calculated (%)                                                                              52.07     6.37      12.65                                       Found (%)     51.99     6.28      12.41                                       ______________________________________                                    

EXAMPLE 3

Into a suspension of 2.0 g (0.0027 mole) of N^(G),N^(G)-dibenzyloxycarbonyl-N²-(6,7-dimethoxy-2-naphthalenesulfonyl)-N-butyl-L-argininamide and 20%palladium-carbon in 50 ml of ethanol and 10 ml of acetic acid was passedhydrogen gas for 10 hours at room temperature. Upon completion of thereaction, the catalyst was filtered off, and the solvent was evaporatedunder reduced pressure to give an oily residue, which was reprecipitatedwith methanol-ether to give N²-(6,7-dimethoxy-2-naphthalenesulfonyl)-N-butyl-L-argininamide acetate inthe powder form in a yield of 78%.

    ______________________________________                                        Elemental analysis: as C.sub.22 H.sub.33 O.sub.5 N.sub.5 S . CH.sub.3         COOH                                                                                      C       H         N                                               ______________________________________                                        Calculated (%)                                                                              53.42     6.91      12.98                                       Found (%)     53.61     6.87      12.71                                       ______________________________________                                    

EXAMPLE 4

To 5.0 ml (0.069 mole) of cold thionyl chloride was added with vigorousstirring 1.0 g (0.00236 mole) of N²-(6,7-dimethoxy-2-naphthalenesulfonyl)-L-arginine, and the reactionmixture was allowed to react at room temperature for 1 hour. After thereaction was complete, 100 ml of dry ether was added to the reactionmixture, and the formed precipitate was collected and washed well with50 ml of dry ether.

The thus obtained powdery N²-(6,7-dimethoxy-2-naphthalenesulfonyl)-L-arginyl chloridedihydrochloride was added with stirring to a solution of 1.2 g (0.012mole) of 4-methyl-piperidine in 10 ml of chloroform, and the mixture wasallowed to stand for 3 hours at room temperature. After the reaction wascomplete, the solvent and the excess 4-methylpiperidine were distilledunder reduced pressure, and the residue was dissolved in 20 ml ofchloroform. The chloroform layer was washed well with saturated NaClaqueous solution and dried over sodium sulfate, and then, the chloroformwas distilled under reduced pressure. Addition of 10 ml of acetic acidand 100 ml of dry ether to the residue resulted in deposition of an oilyproduct. The ether was removed by decantation, and the oily product waswashed well with dry ether to give powdery 4-methyl-1-[N²-(6,7-dimethoxy-2-naphthalenesulfonyl)-L-arginyl]piperidine monoacetate.Yield 1.1 g (84%).

    ______________________________________                                        Elemental analysis: as C.sub.24 H.sub.35 N.sub.5 O.sub.5 S . CH.sub.3         COOH                                                                                      C       H       N                                                 ______________________________________                                        Calculated (%)                                                                              55.21     6.95      12.38                                       Found (%)     55.11     6.74      12.01                                       ______________________________________                                    

EXAMPLE 5

To a suspension of 1.00 g (0.00236 mole) of N²-(6,7-dimethoxy-2-naphthalenesulfonyl)-L-arginine in 20 ml oftetrahydrofuran was added little by little 0.98 g (0.0047 mole) ofphosphorus pentachloride while cooling with ice water. The mixture wasstirred for 1 hour at 0°-5° C., and then, for 2 hours at roomtemperature. To this reaction mixture was added 100 ml of dry ether, andthe supernatant was removed by decantation. The residual oily productwas washed with 50 ml of dry ether to give powdery N²-(6,7-dimethoxy-2-naphthalenesulfonyl)-L-arginyl chloridedihydrochloride, which was added with stirring to a solution of 1.31 g(0.015 mole) of N-methyl-N-butylamine in 10 ml of chloroform.Thereafter, following the same procedures as described in Example 1, N²-(6,7-dimethoxy-2-naphthalenesulfonyl)-N-methyl-N-butyl-L-argininamidemonoacetate was obtained. Yield 0.76 g (58%).

    ______________________________________                                        Elemental analysis: as C.sub.23 H.sub.35 N.sub.5 O.sub.5 S . CH.sub.3         COOH                                                                                      C       H         N                                               ______________________________________                                        Calculated (%)                                                                              54.24     7.10      12.65                                       Found (%)     54.00     7.21      12.46                                       ______________________________________                                    

EXAMPLE 6

To a solution of 1.0 g (0.004 mole) of L-arginine ethyl esterdihydrochloride in 50 ml of dichloromethane and 1.15 g (0.012 mole) oftriethylamine was added 1.14 g (0.004 mole) of4,6-dimethoxy-2-naphthalenesulfonyl chloride with stirring at roomtemperature.

After stirring for 5 hours at room temperature, the reaction mixture waswashed with water to remove the formed triethylamine hydrochloride.After the solution was dried over sodium sulfate, the dichloromethanewas evaporated under reduced pressure, to give N²-(4,6-dimethoxy-2-naphthalenesulfonyl)-L-arginine ethyl ester.

To this product was added ethyl ether, and then hydrogen chloride waspassed. The formed precipitate was filtered to give N²-(4,6-dimethoxy-2-naphthalenesulfonyl)-L-arginine ethyl esterhydrochloride in the form of a powder. Yield 84%.

    ______________________________________                                        Elemental analysis: as C.sub.20 H.sub.29 O.sub.6 N.sub.4 SCl                              C       H         N                                               ______________________________________                                        Calculated (%)                                                                              49.13     5.97      11.46                                       Found (%)     48.96     6.15      11.52                                       ______________________________________                                    

EXAMPLE 7

To a suspension of 1.50 g (0.005 mole) of L-arginine butyl esterdihydrochloride in a solution consisting of 1.4 g of potassium carbonateand 10 ml of water, which had been cooled to 0-5° C, was added dropwiseof 1.43 g (0.005 mole) of 6,7-dimethoxy-2-naphthalenesulfonyl chloridein 10 ml of ethyl ether with vigorous stirring over a period of 30minutes.

The mixture was stirred for further 10 minutes and a viscous deposit wasobtained. The solvent was removed by decantation, and the residualdeposit was washed with water and ether.

To a suspension of the resulting product in 20 ml of ethyl ether wasadded 2 g of p-toluenesulfonic acid morohydrate with stirring to yield acrystal, which was filtered and washed several times with ethyl ether togive N² -(6,7-dimethoxy-2-naphthalenesulfonyl)-L-arginine butyl esterp-toluenesulfonate in 92% yield; m.p. 113°-115° C.

    ______________________________________                                        Elemental analysis: as C.sub.29 H.sub.40 O.sub.9 N.sub.4 S.sub.2                          C       H         N                                               ______________________________________                                        Calculated (%)                                                                              53.36     6.18      8.59                                        Found (%)     53.23     6.14      8.70                                        ______________________________________                                    

EXAMPLE 8

To a mixture of 1.00 g (0.0037 mole) of 4-ethyl-1-(L-arginyl) piperdineand 0.61 g (0.0044 mole) of potassium carbonate in 10 ml of water, whichhad been cooled to 0° C., was added dropwise a solution of 1.25 g(0.0044 mole) of 6.7-dimethoxy-2-naphthalenesulfonyl chloride in 30 mlof dioxane with vigorous stirring over a period of 30 minutes. Thereaction mixture was stirred for additional 5 hours at room temperatureand the formed precipitate was removed by filtration. The solvent wasevaporated under reduced pressure, and to the residue was added 50 ml ofchloroform. The undissolved material was filtered off and the solutionwas dried over sodium sulfate. Addition of 10 ml of acetic acid to thissolution followed by evaporation of the solvent gave a viscous oilyproduct, which was reprecipitated with methanol-ethyl ether to afford4-ethyl-1-[N²-(6,7-dimethoxy-2-naphthalenesulfonyl)-L-arginyl]piperidine acetate in a62% yield.

    ______________________________________                                        Elemental analysis: as C.sub.24 H.sub.35 O.sub.7 N.sub.5 S                                C       H         N                                               ______________________________________                                        Calculated (%)                                                                              55.01     7.28      12.34                                       Found (%)     54.93     7.14      12.28                                       ______________________________________                                    

EXAMPLE 9

To a solution of 1.00 g (0.0041 mole) of 4-(L-arginyl) morpholine in 50ml of chloroform and 0.52 g (0.0052 mole) of triethylamine was added1.48 g (0.0052 mole) of 6,7-dimethoxy-2-naphthalenesulfonyl chloridewith stirring at room temperature.

After stirring for 5 hours at room temperature, the reaction mixture wasslurried with 10 ml of water.

The aqueous layer was separated, and the residual chloroform layer wasdried over sodium sulfate. Addition of 2 ml of acetic acid to thechloroform layer followed by evaporation of chloroform gave a viscousoily residue, which was reprecipitated with methanol-ethyl ether toafford 4-[N² -(6,7-dimethoxy-2-naphthalenesulfonyl)-L-arginyl]morpholineacetate in a 66% yield.

    ______________________________________                                        Elemental analysis: as C.sub.21 H.sub.29 O.sub.8 N.sub.5 S                                C       H         N                                               ______________________________________                                        Calculated (%)                                                                              52.07     6.37      12.65                                       Found (%)     51.88     6.26      12.26                                       ______________________________________                                    

EXAMPLE 10

To a suspension of 1.0 g of N²-(4,6-dimethoxy-2-naphthalenesulfonyl)-L-arginine in 30 ml of ethanolwas added little by little 1 ml of thionyl chloride with stirring. Thesuspension soon became a clear solution. After the solution was refluxedwith stirring for 4 hours, the ethanol was distilled away under reducedpressure, to give a viscous oily residue, which was washed well threetimes with 20 ml of ethyl ether to afford colorless and powdery N²-(4,6-dimethoxy-2-naphthalenesulfonyl)-L-arginine ethyl esterhydrochloride in a 96% yield.

    ______________________________________                                        Elemental analysis: as C.sub.20 H.sub.29 O.sub.6 N.sub.4 SCl                              C       H         N                                               ______________________________________                                        Calculated (%)                                                                              49.13     5.97      11.46                                       Found (%)     48.96     6.15      11.52                                       ______________________________________                                    

EXAMPLE 11

A mixture of 1.0 g of N²-(6,7-dimethoxy-2-naphthalenesulfonyl)-L-arginine and 1.0 g ofp-toluenesulfonic acid monohydrate in 5 ml of butyl alcohol and 30 ml ofbenzene was refluxed for 5 hours, while removing the water formed duringthe reaction. The reaction mixture was concentrated under reducedpressure, and to the residue was added ethyl ether to yield acrystalline substance which was collected by filtration, washed severaltimes with ethyl ether to afford N²-(6,7-dimethoxy-2-naphthalenesulfonyl)-L-arginine butyl esterp-toluenesulfonate: yield 92%, m.p. 113-115° C.

    ______________________________________                                        Elemental analysis: as C.sub.29 H.sub.40 O.sub.9 N.sub.4 S.sub.2                          C       H         N                                               ______________________________________                                        Calculated (%)                                                                              53.36     6.18      8.59                                        Found (%)     53.23     6.14      8.70                                        ______________________________________                                    

EXAMPLE 12

To 1.2 g (0.0020 mole) of 4-ethyl-1-[N^(G) -nitro-N²-(6-chromansulfonyl)-L-arginyl]piperidine was added 0.64 g (0.0060 mole)of anisole and 3 ml of hydrogen fluride while cooling withDry-ice/acetone, and the mixture was stirred for 30 minutes in an icebath. The excess hydrogen fluoride was evaporated at reduced pressurewith cooling to afford an oily product, which was slurried with 100 mlof dry ethyl ether. The ether layer was separated by decantation, andthe obtained powder was dissolved in methanol, reprecipitated with ethylether, and then filtered to give 4-ethyl-1-[N²-(6-chromansulfonyl)-L-arginyl]piperidine hydrofluoride in the powderform in a yield of 63%.

    ______________________________________                                        Elemental analysis: as C.sub.22 H.sub.36 O.sub.4 N.sub.5 S . HF                           C       H         N                                               ______________________________________                                        Calculated (%)                                                                              54.41     7.47      14.42                                       Found (%)     54.70     7.45      14.31                                       ______________________________________                                    

EXAMPLE 13

Into a suspension of 1.2 g (0.0020 mole) of 4-ethyl-1-[N^(G) -nitro-N²-(1,4-benzodioxane-6-sulfonyl)-L-arginyl] piperidine and 0.1 g ofpalladium black in 30 ml of ethanol and 10 ml of acetic acid was passedhydrogen gas for 30 hours at room temperature. Upon completion of thereaction, the catalyst was filtered off, and the solvent was evaporatedunder reduced pressure to give a viscous oily residue, which was takenup in methanol and reprecipitated with ethyl ether to afford4-ethyl-1-[N² -(1,4-benzodioxane-6-sulfonyl)-L-arginyl]piperidineacetate in the powder form in a yield of 85%.

    ______________________________________                                        Elemental analysis: as C.sub.21 H.sub.33 O.sub.5 N.sub.5 S . CH.sub.3         COOH                                                                                      C       H         N                                               ______________________________________                                        Calculated (%)                                                                              52.35     17.07     13.27                                       Found (%)     52.65     7.01      13.12                                       ______________________________________                                    

EXAMPLE 14

Into a suspension of 2.0 g (0.0026 mole) of 4-ethyl-1-[N^(G), N^(G)-dibenzyloxycarbonyl-N²-(2H-3,4-dihydro-1,5-benzodioxepin-7-sulfonyl)-L-arginyl]piperidine and10% palladium-carbon in 50 ml of ethanol and 10 ml of acetic acid waspassed hydrogen gas for 10 hours at room temperature. Upon completion ofthe reaction, the catalyst was filtered off, and the solvent wasevaporated under reduced pressure to give a viscous oily residue, whichwas reprecipitated with methanol-ether to give 4-ethyl-1-[N²-(2H-3,4-dihydro-1,5-benzodioxepin-7-sulfonyl)-L-arginyl]piperidineacetate in the powder form in a yield of 81%.

    ______________________________________                                        Elemental analysis: as C.sub.24 H.sub.39 O.sub.7 N.sub.5 S . CH.sub.3         COOH                                                                                      C       H         N                                               ______________________________________                                        Calculated (%)                                                                              53.22     7.26      12.93                                       Found (%)     53.51     7.04      12.87                                       ______________________________________                                    

Various other N² -substituted-L-arginine esters and amides weresynthesized in accordance with the procedures of the above examples. Theresults, including those of the above examples, are summarized inTABLE 1. In TABLE 1, N² -substituted-L-arginine esters and amidesrepresented by the general formula (I) are shown by indicating R and R'in the formula and addition moieties.

    TABLE 1      ##STR35##      Addition Concentrationrequired toprolong thecoagulationtime by afactor     of two Preparationprocess Propertyor Elemental analysisUpper: CalculatedL     ower: Found I.R. (KBr) No.      R R' Moiety (μM) (Ex. No.) m.p. (°      C) C H N (cm.sup.-1)                    1 O-n-C.sub.3      H.sub.7     ##STR36##      ##STR37##      1.0 11 130-133 52.66 52.57 6.005.89 8.778.66 2 O-n-C.sub.4 H.sub.9      ##STR38##      ##STR39##      0.2 7 113-115 53.3653.23 6.186.14 8.598.70 3 O-n-C.sub.6 H.sub.13      ##STR40##      ##STR41##      0.6 11 107-112 54.7054.83 6.516.40 8.238.29 4      ##STR42##      ##STR43##      ##STR44##      0.35 11 powder 55.4855.36 5.535.29 8.098.19 5 OCH.sub.2 CH.sub.2     CH.sub.2      Cl     ##STR45##      ##STR46##      0.15 11 100-105 49.9649.89 5.545.39 8.328.49 6      ##STR47##      ##STR48##      ##STR49##      15 11 125-130 54.8654.69 6.246.22 8.258.31 7 OCH.sub.2 CH.sub.2     OCH.sub.3      ##STR50##      ##STR51##      0.25 11 104-107 51.3751.44 5.855.76 5.368.57 8 OCH.sub.2 CH.sub.2 CCH      ##STR52##      ##STR53##      1.5 11 127-131 53.69 53.54 5.595.32 8.648.46 9 OCH.sub.2 CHCHCH.sub.3      ##STR54##      ##STR55##      1.5 11 powder 53.5353.29 5.885.97 8.618.69 10 O-n-C.sub.4 H.sub.9      ##STR56##      ##STR57##      50 11 94-98 54.7054.66 6.516.42 8.298.53 11 OCH.sub.2 CH.sub.2      OCH.sub.3      ##STR58##      ##STR59##      23< 11 100-105 51.4251.51 6.326.54 7.998.02 12 OCH.sub.2 CH CHCH.sub.3      ##STR60##      ##STR61##      4.5 11 powder 54.8654.98 6.246.12 8.258.30 13 O-n-C.sub.4 H.sub.9      ##STR62##      ##STR63##      5.5 11 148-151 53.3653.50 6.186.20 8.598.60 14      ##STR64##      ##STR65##      CH.sub.3 COOH 0.15 4 powder 55.2155.11 6.956.74 12.3812.01 3,300        1     (broad),635 15      ##STR66##      ##STR67##      CH.sub.3      COOH 0.15 8 powder 55.0154.93 7.287.14 12.3412.28 3,3803,1801,635 16      ##STR68##      ##STR69##      HF 0.15 1 powder 55.6455.50 7.107.12 12.9812.87 17      ##STR70##      ##STR71##      CH.sub.3      COOH 0.55 2 powder 55.2155.04 6.956.78 12.3812.26 18     ##STR72##      ##STR73##      CH.sub.3      COOH 1.5 9 powder 52.0751.88 6.376.26 12.6512.26 3,3603,1801,640 19      ##STR74##      ##STR75##      CH.sub.3      COOH 0.60 2 powder 53.6953.48 6.726.68 12.0412.00 20     ##STR76##      ##STR77##      2CH.sub.3      COOH 4.0 2 powder 51.7551.49 6.766.39 13.4113.21 3,4003,2001,640 21      ##STR78##      ##STR79##      2HF 4.0 1 powder 50.5450.48 6.646.21 15.3715.28 22      ##STR80##      ##STR81##      CH.sub.3      COOH 1.5 3 powder 52.5152.40 6.446.39 14.1314.09 23     ##STR82##      ##STR83##      CH.sub.3 COOH  3 powder 53.4253.39 6.916.72 12.9812.73 3,3801,650 24      ##STR84##      ##STR85##      CH.sub.3 COOH 0.5 5 powder 51.0150.87 6.516.43 12.9312.81 3,300     (broad)1,640 25      ##STR86##      ##STR87##      CH.sub.3      COOH 7.0 5 powder 50.6051.00 6.196.21 12.3012.28 3,4003,2001,7401,665     26      ##STR88##      ##STR89##      CH.sub.3 COOH 7.0 5 powder 51.4551.37 6.396.26 12.0011.69 3,200     (broad)1,7201,640 (broad) 27      ##STR90##      ##STR91##      CH.sub.3      COOH 10 3 powder 56.1456.01 6.816.46 12.1312.00 3,300 (broad)1,635 28      ##STR92##      ##STR93##      CH.sub.3      COOH 7.0 3 powder 52.2552.21 6.586.48 11.7211.56 29     ##STR94##      ##STR95##      CH.sub.3      COCH 7.0 3 powder 53.0252.67 6.766.41 11.4511.04 30     ##STR96##      ##STR97##      CH.sub.3      COOH 30 3 powder 55.7555.81 7.457.22 12.04 12.34 3,3601,6301,2601,140     31      ##STR98##      ##STR99##      CH.sub.3      COOH 8.5 3 powder 56.6456.51 7.707.65 11.8011.98 3,3501,6401,2601,160     32      ##STR100##      ##STR101##      CH.sub.3      COOH 0.075 3 powder 55.2154.93 6.956.73 12.3812.15 33     ##STR102##      ##STR103##      CH.sub.3      COOH 0.10 3 powder 55.0154.84 7.287.16 12.3412.03 34     ##STR104##      ##STR105##       CH.sub.3      COOH 5.5 3 powder 57.3157.55 7.467.71 11.5211.32 3,3501,6801,160 35      ##STR106##      ##STR107##      CH.sub.3      COOH 0.8 3 powder 56.7356.75 5.825.71 12.2511.98 3,3501,6501,150 36      ##STR108##      ##STR109##      HF 15 12 powder 54.4154.70 7.477.45 14.4214.31 3,300 (broad)1,640 37      ##STR110##      ##STR111##      CH.sub.3 COOH 25 13 powder 52.3552.65 7.077.01 13.2713.12 3,3201,640 38      ##STR112##      ##STR113##      CH.sub.3      COOH 5 14 powder 53.2253.31 7.267.04 12.9312.87 3,350 (broad)1,635 39      ##STR114##      ##STR115##      CH.sub.3      COOH 8 13 powder 52.3552.60 7.076.93 13.2713.40 3,100 (broad)1,640 40      ##STR116##      ##STR117##      CH.sub.3      COOH 25 14 powder 48.9249.21 6.456.45 13.5813,41 3,4003,1201,640 41      ##STR118##      ##STR119##      CH.sub.3      COOH 100 13 powder 51.2551.53 7.237.46 13.5813.29 3,3501,6401,280 42      ##STR120##      ##STR121##      -- 6 13 powder 53.9953.75 7.297.61 13.6913.50 3,4001,630 43      ##STR122##      ##STR123##      CH.sub.3      COOH 0.3 13 powder 58.6258.32 6.856.58 12.2111.99 3,3401,6301,265 44      ##STR124##      ##STR125##      1/2H.sub.2      O 0.3 13 powder 59.0358.84 6.546.48 13.7713.63 3,3501,6301,275 45      ##STR126##      ##STR127##      CH.sub.3      COOH 0.2 13 powder 57.9457.64 6.666.65 12.5112.24 3,3501,630 1,160 46      ##STR128##      ##STR129##      CH.sub.3      COOH 0.15 13 powder 56.3356.08 6.486.45 12.1711.96 3,3001,6301,290 47      ##STR130##      ##STR131##     CH.sub.3      COOH 0.5 13 powder 57.2357.01 6.476.41 12.8412.61 3,3501,6351,270 48      ##STR132##      ##STR133##      CH.sub.3      COOH 5 13 powder 57.0256.74 6.816.93 12.7912.65 3,3101,6401,260

What is claimed as new and intended to be covered by letters patentis:
 1. An N² -substituted-L-argininamide having the formula: ##STR134##and the pharmaceutically acceptable acid addition salts thereof, whereinR is ##STR135## wherein Z is a divalent group which consists of at leasttwo groups selected from methylene --CH₂ -- and monosubstitutedmethylene ##STR136## wherein R₄ is selected from the group consisting ofC₁ -C₁₀ alkyl and C₁ -C₁₀ alkoxy, and at least one group selected fromthe group consisting of oxy --O--, thio --S--, alkyl substituted imino##STR137## wherein R₅ is C₁ -C₁₀ alkyl, and acyl substituted imino##STR138## wherein R₆ is C₁ -C₁₀ alkyl, which are combined in anarbitrary order, the number of the combined groups being up to 20; andR' is selected from the group consisting of ##STR139## wherein R" andR"' when considered separately are C₁ -C₁₀ alkyl, or R" and R"' whentaken together are C₁ -C₁₀ alkylene; ##STR140##
 2. The compounds ofclaim 1, wherein R is selected from the group consisting oftetrahydro-1, n-oxazin-n-yl, wherein n is an integer of 2, 3 or 4;tetrahydro-1, n-thiazin-n-yl, wherein n is an integer of 2, 3 or 4;1-piperazinyl substituted with a group selected from C₁ -C₅ alkyl and C₁-C₅ acyl; and R' is selected from the group consisting of ##STR141##wherein R" and R"' when considered separately are C₁ -C₅ alkyl, or R"and R"' when taken together are C₁ -C₅ alkylene; ##STR142##
 3. Thecompounds of claim 2, wherein R is selected from the group consistingof, morpholine, tetrahydro-1,4-thiazin-4-yl, 4-methyl-1-piperazinyl and4-acetyl-1-piperazinyl; and R' is selected from the group consisting of##STR143##
 4. The compound of claim 1 which is 4-[N²-(6,7-dimethoxy-2-naphthalenesulfonyl)-L-arginyl] morpholine.
 5. Apharmaceutical composition which comprises an amount of a compound ofcliam 1, effective for inhibiting activity and suppressing activation ofthrombin in vivo, and a pharmaceutically acceptable carrier.